Hi all,
Since 2 days i am new to linux. Today i wanted to install company of heroes 2 from steam on linux. I saw i have lost alot of GB's so i wonder where that did go. Can someone tell me what flatpak is and why it is so big and can those be deleted ????. The only thing i did install from the zorin os appstore is Wine, Winetricks, Lutris and Steam to try windows games on Linux (so far i am a noob to get this to work lol).
Yes, you can remove flatpak and everything in it.
Open a terminal with the keyboard shortcut ctrl+alt+t
Enter in
flatpak list
This will list out all flatpaks installed. While it may look like a lot of things you need, you would only need them if you were running a lot of flatpak applications.
flatpak uninstall --unused
sudo apt remove --autoremove flatpak
sudo apt purge flatpak
Thanks for your answer, is it by default zorin use so much ?
Only if you use flat/snap. they eat alot of space...
Let me try to understand this since i am new to linux, this all comes from the app store ?. I installed this OS 2 days ago. So far i only installed some os updates and Wine, winetricks, steam and lutris from the appstore.
So by default the folder is that big ?
It's because each and every app you install comes with its own libraries in Flat, where linux/zorin by traditional way share it's libs among installed apps.
@storm, So far i only installed some os updates and Wine, winetricks, steam and lutris from the software/appstore. I did reinstall them a few times, but i don't think they make dupe lib folders. Still i don't think those 15,3GB are from those few apps i installed in 2 days.
Is there a way i can view the var folder as root user ?
Easily, you can view all of root safely within your file manager. If using Nautilus (The default Files) then click the "other locations" selection in the Left Sidepane.
Then Computer - and start at Root. You can see var listed as a directory. You will not have write permissions to change anything unless you elevate to root. But I wouldn't recommend doing that until you have used the OS a little while and grown familiarity.
Without access to your drive, we cannot tell you what is taking up space.
Open a terminal with the keyboard shortcut ctrl+alt+t and run the command:
sudo apt install ncdu
Once it is installed, run
ncdu
This will print out your Space Hogs on the drive. (There is also a good packages for doing this included in the Debian Goodies bundle, but I am in a hurry and cannot go searching that right now. I posted a thread about it back in prehistory...)
It's the flatpaks. You can remove them as described in the second post.
While the standard system of Linux to share libraries is technically more efficient on drive space, I don't think its the best option. All you have to do is make the mistake of removing certain apps, and the libraries might go with it, rendering another app unusable.
I like that flatpack comes with its own libraries, that way you can always insure, that the APP is going to work. And IMO, that makes it a much more user friendly option, for Linux beginners.
Well, the problem is the sandbox nature of Flatpak.
As I repeatedly said in this forum, Flatpak version of OnlyOffice is unable to connect to a network printer nor a network drive, making it next to useless as an office suite. I could not override this and I do not think this is particularly beginner friendly.
If you were having that issue, I can most certainly agree with that sentiment, that is not user friendly for beginners. 
Your best bet is to remove flatpak as aravisian suggested earlier. You can search each program you use in your favorite search engine:
How to install steam in terminal Ubuntu 20.04
Zorin 16 is based on Ubuntu 20.04, though with the updated kernel you could also use Ubuntu 21.04. Don't use any suggestion of snap or flatpak, usually the method you want adds a repository (ppa) under apt or a .deb file (click to install). Sometimes you'll get a tarball (.tar.gz) which requires make (instructions are included in the how to and a read me file in the archive). This makes updates easier and no problems with the sandboxing of apps in snap/flatpak.
It's worth it because software uses such little space then and no issues with system integration.
I normally do the minimal install, remove any software i don't use and begin installing what i do use.
Maybe i missed the minimal option, i dont know. Will delete some stock apps and hope i get some space back
So i followed Aravisian's suggestion and removed the flatpak stuff...Still there are some traces left. Any idea if i need those and how i can remove them ???
If you already performed the following in terminal:
sudo apt remove flatpak --purge
Then you can delete any left over directories by:
sudo rm -r ~/flatpak ~/.local/share/flatpak /usr/share/flatpak
If they haven't already been removed
/var/lib/flatpack may contain leftover data, as well.
Not bad for doing it from memory though
Thanks for the new sudo command, will try it out when i am behind my laptop again.
I also want to understand the command a bit more
rm = remove ?
-r = ?